2020-03-14 13:06:40 +01:00
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#![cfg(not(feature = "no_optimize"))]
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2020-03-17 03:27:43 +01:00
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use crate::any::{Any, Dynamic};
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use crate::engine::{
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2020-03-19 12:53:42 +01:00
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Engine, FnCallArgs, KEYWORD_DEBUG, KEYWORD_DUMP_AST, KEYWORD_EVAL, KEYWORD_PRINT,
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KEYWORD_TYPE_OF,
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2020-03-17 03:27:43 +01:00
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};
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2020-03-17 10:33:37 +01:00
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use crate::parser::{map_dynamic_to_expr, Expr, FnDef, ReturnType, Stmt, AST};
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2020-03-14 07:30:44 +01:00
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use crate::scope::{Scope, ScopeEntry, VariableType};
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2020-03-09 14:57:07 +01:00
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2020-03-17 19:26:11 +01:00
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use crate::stdlib::{
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2020-03-18 11:41:18 +01:00
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boxed::Box,
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string::{String, ToString},
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2020-03-17 19:26:11 +01:00
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sync::Arc,
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2020-03-18 11:41:18 +01:00
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vec,
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vec::Vec,
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2020-03-17 19:26:11 +01:00
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};
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2020-03-15 15:39:58 +01:00
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2020-03-18 03:36:50 +01:00
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/// Level of optimization performed.
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2020-03-15 15:39:58 +01:00
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#[derive(Debug, Eq, PartialEq, Hash, Clone, Copy)]
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pub enum OptimizationLevel {
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2020-03-18 03:36:50 +01:00
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/// No optimization performed.
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2020-03-15 15:39:58 +01:00
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None,
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2020-03-18 03:36:50 +01:00
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/// Only perform simple optimizations without evaluating functions.
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2020-03-15 15:39:58 +01:00
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Simple,
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/// Full optimizations performed, including evaluating functions.
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2020-03-18 03:36:50 +01:00
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/// Take care that this may cause side effects as it essentially assumes that all functions are pure.
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2020-03-15 15:39:58 +01:00
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Full,
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}
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2020-03-18 03:36:50 +01:00
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/// Mutable state throughout an optimization pass.
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2020-03-15 15:39:58 +01:00
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struct State<'a> {
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2020-03-18 03:36:50 +01:00
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/// Has the AST been changed during this pass?
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2020-03-13 11:12:41 +01:00
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changed: bool,
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2020-03-18 03:36:50 +01:00
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/// Collection of constants to use for eager function evaluations.
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2020-03-13 11:12:41 +01:00
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constants: Vec<(String, Expr)>,
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2020-03-18 03:36:50 +01:00
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/// An `Engine` instance for eager function evaluation.
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engine: &'a Engine<'a>,
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2020-03-13 11:12:41 +01:00
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}
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2020-03-15 15:39:58 +01:00
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impl State<'_> {
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2020-03-18 03:36:50 +01:00
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/// Reset the state from dirty to clean.
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2020-03-15 15:39:58 +01:00
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pub fn reset(&mut self) {
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self.changed = false;
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}
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2020-03-18 03:36:50 +01:00
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/// Set the AST state to be dirty (i.e. changed).
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2020-03-13 11:12:41 +01:00
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pub fn set_dirty(&mut self) {
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self.changed = true;
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}
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2020-03-18 03:36:50 +01:00
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/// Is the AST dirty (i.e. changed)?
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2020-03-13 11:12:41 +01:00
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pub fn is_dirty(&self) -> bool {
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self.changed
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}
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2020-03-18 03:36:50 +01:00
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/// Does a constant exist?
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2020-03-13 11:12:41 +01:00
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pub fn contains_constant(&self, name: &str) -> bool {
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self.constants.iter().any(|(n, _)| n == name)
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}
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2020-03-18 03:36:50 +01:00
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/// Prune the list of constants back to a specified size.
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2020-03-13 11:12:41 +01:00
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pub fn restore_constants(&mut self, len: usize) {
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self.constants.truncate(len)
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}
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2020-03-18 03:36:50 +01:00
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/// Add a new constant to the list.
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2020-03-13 11:12:41 +01:00
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pub fn push_constant(&mut self, name: &str, value: Expr) {
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self.constants.push((name.to_string(), value))
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}
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2020-03-18 03:36:50 +01:00
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/// Look up a constant from the list.
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2020-03-13 11:12:41 +01:00
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pub fn find_constant(&self, name: &str) -> Option<&Expr> {
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for (n, expr) in self.constants.iter().rev() {
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if n == name {
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return Some(expr);
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}
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}
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None
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}
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}
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2020-03-18 03:36:50 +01:00
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/// Optimize a statement.
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2020-03-15 15:39:58 +01:00
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fn optimize_stmt<'a>(stmt: Stmt, state: &mut State<'a>, preserve_result: bool) -> Stmt {
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2020-03-09 14:57:07 +01:00
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match stmt {
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2020-03-18 03:36:50 +01:00
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// if expr { Noop }
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Stmt::IfElse(expr, if_block, None) if matches!(*if_block, Stmt::Noop(_)) => {
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2020-03-13 11:12:41 +01:00
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state.set_dirty();
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2020-03-12 16:46:52 +01:00
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let pos = expr.position();
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2020-03-13 11:12:41 +01:00
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let expr = optimize_expr(*expr, state);
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2020-03-12 16:46:52 +01:00
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2020-03-18 03:36:50 +01:00
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if preserve_result {
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// -> { expr, Noop }
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Stmt::Block(vec![Stmt::Expr(Box::new(expr)), *if_block], pos)
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2020-03-14 16:41:15 +01:00
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} else {
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2020-03-18 03:36:50 +01:00
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// -> expr
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Stmt::Expr(Box::new(expr))
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2020-03-12 16:46:52 +01:00
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}
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}
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2020-03-18 03:36:50 +01:00
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// if expr { if_block }
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Stmt::IfElse(expr, if_block, None) => match *expr {
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// if false { if_block } -> Noop
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2020-03-09 14:57:07 +01:00
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Expr::False(pos) => {
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2020-03-13 11:12:41 +01:00
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state.set_dirty();
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2020-03-09 14:57:07 +01:00
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Stmt::Noop(pos)
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}
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2020-03-18 03:36:50 +01:00
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// if true { if_block } -> if_block
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Expr::True(_) => optimize_stmt(*if_block, state, true),
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// if expr { if_block }
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2020-03-10 04:22:41 +01:00
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expr => Stmt::IfElse(
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2020-03-13 11:12:41 +01:00
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Box::new(optimize_expr(expr, state)),
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2020-03-18 03:36:50 +01:00
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Box::new(optimize_stmt(*if_block, state, true)),
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2020-03-09 14:57:07 +01:00
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None,
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),
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},
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2020-03-18 03:36:50 +01:00
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// if expr { if_block } else { else_block }
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Stmt::IfElse(expr, if_block, Some(else_block)) => match *expr {
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// if false { if_block } else { else_block } -> else_block
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Expr::False(_) => optimize_stmt(*else_block, state, true),
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// if true { if_block } else { else_block } -> if_block
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Expr::True(_) => optimize_stmt(*if_block, state, true),
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// if expr { if_block } else { else_block }
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2020-03-10 04:22:41 +01:00
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expr => Stmt::IfElse(
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2020-03-13 11:12:41 +01:00
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Box::new(optimize_expr(expr, state)),
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2020-03-18 03:36:50 +01:00
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Box::new(optimize_stmt(*if_block, state, true)),
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match optimize_stmt(*else_block, state, true) {
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stmt if matches!(stmt, Stmt::Noop(_)) => None, // Noop -> no else block
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2020-03-12 16:46:52 +01:00
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stmt => Some(Box::new(stmt)),
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},
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2020-03-09 14:57:07 +01:00
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),
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},
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2020-03-18 03:36:50 +01:00
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// while expr { block }
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Stmt::While(expr, block) => match *expr {
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// while false { block } -> Noop
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2020-03-09 14:57:07 +01:00
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Expr::False(pos) => {
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2020-03-13 11:12:41 +01:00
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state.set_dirty();
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2020-03-09 14:57:07 +01:00
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Stmt::Noop(pos)
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}
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2020-03-18 03:36:50 +01:00
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// while true { block } -> loop { block }
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Expr::True(_) => Stmt::Loop(Box::new(optimize_stmt(*block, state, false))),
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// while expr { block }
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expr => match optimize_stmt(*block, state, false) {
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// while expr { break; } -> { expr; }
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2020-03-17 10:33:37 +01:00
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Stmt::Break(pos) => {
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// Only a single break statement - turn into running the guard expression once
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state.set_dirty();
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let mut statements = vec![Stmt::Expr(Box::new(optimize_expr(expr, state)))];
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if preserve_result {
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statements.push(Stmt::Noop(pos))
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}
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Stmt::Block(statements, pos)
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}
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2020-03-18 03:36:50 +01:00
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// while expr { block }
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2020-03-17 10:33:37 +01:00
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stmt => Stmt::While(Box::new(optimize_expr(expr, state)), Box::new(stmt)),
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},
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},
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2020-03-18 03:36:50 +01:00
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// loop { block }
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Stmt::Loop(block) => match optimize_stmt(*block, state, false) {
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// loop { break; } -> Noop
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2020-03-17 10:33:37 +01:00
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Stmt::Break(pos) => {
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// Only a single break statement
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state.set_dirty();
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Stmt::Noop(pos)
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}
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2020-03-18 03:36:50 +01:00
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// loop { block }
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2020-03-17 10:33:37 +01:00
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stmt => Stmt::Loop(Box::new(stmt)),
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2020-03-09 14:57:07 +01:00
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},
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2020-03-18 03:36:50 +01:00
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// for id in expr { block }
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Stmt::For(id, expr, block) => Stmt::For(
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2020-03-09 14:57:07 +01:00
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id,
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2020-03-13 11:12:41 +01:00
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Box::new(optimize_expr(*expr, state)),
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2020-03-18 03:36:50 +01:00
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Box::new(optimize_stmt(*block, state, false)),
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2020-03-09 14:57:07 +01:00
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),
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2020-03-18 03:36:50 +01:00
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// let id = expr;
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2020-03-09 14:57:07 +01:00
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Stmt::Let(id, Some(expr), pos) => {
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2020-03-13 11:12:41 +01:00
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Stmt::Let(id, Some(Box::new(optimize_expr(*expr, state))), pos)
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2020-03-09 14:57:07 +01:00
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}
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2020-03-18 03:36:50 +01:00
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// let id;
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2020-03-09 14:57:07 +01:00
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Stmt::Let(_, None, _) => stmt,
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2020-03-18 03:36:50 +01:00
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// { block }
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Stmt::Block(block, pos) => {
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let orig_len = block.len(); // Original number of statements in the block, for change detection
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let orig_constants_len = state.constants.len(); // Original number of constants in the state, for restore later
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2020-03-09 14:57:07 +01:00
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2020-03-18 03:36:50 +01:00
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// Optimize each statement in the block
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let mut result: Vec<_> = block
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.into_iter()
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2020-03-13 11:12:41 +01:00
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.map(|stmt| {
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if let Stmt::Const(name, value, pos) = stmt {
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2020-03-18 03:36:50 +01:00
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// Add constant into the state
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2020-03-13 11:12:41 +01:00
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state.push_constant(&name, *value);
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state.set_dirty();
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Stmt::Noop(pos) // No need to keep constants
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} else {
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2020-03-18 03:36:50 +01:00
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// Optimize the statement
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optimize_stmt(stmt, state, preserve_result)
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2020-03-13 11:12:41 +01:00
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}
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})
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2020-03-09 14:57:07 +01:00
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.collect();
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2020-03-11 16:43:10 +01:00
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// Remove all raw expression statements that are pure except for the very last statement
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let last_stmt = if preserve_result { result.pop() } else { None };
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2020-03-10 04:22:41 +01:00
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2020-03-17 10:33:37 +01:00
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result.retain(|stmt| !stmt.is_pure());
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2020-03-11 16:43:10 +01:00
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if let Some(stmt) = last_stmt {
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result.push(stmt);
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}
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// Remove all let statements at the end of a block - the new variables will go away anyway.
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// But be careful only remove ones that have no initial values or have values that are pure expressions,
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// otherwise there may be side effects.
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let mut removed = false;
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while let Some(expr) = result.pop() {
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match expr {
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Stmt::Let(_, None, _) => removed = true,
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Stmt::Let(_, Some(val_expr), _) if val_expr.is_pure() => removed = true,
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_ => {
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result.push(expr);
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break;
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}
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}
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}
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if preserve_result {
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if removed {
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result.push(Stmt::Noop(pos))
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}
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2020-03-18 03:36:50 +01:00
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// Optimize all the statements again
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2020-03-11 16:43:10 +01:00
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result = result
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.into_iter()
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.rev()
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.enumerate()
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2020-03-18 03:36:50 +01:00
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.map(|(i, s)| optimize_stmt(s, state, i == 0))
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2020-03-11 16:43:10 +01:00
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.rev()
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.collect();
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2020-03-10 04:22:41 +01:00
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}
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2020-03-17 10:33:37 +01:00
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// Remove everything following the the first return/throw
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let mut dead_code = false;
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result.retain(|stmt| {
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if dead_code {
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return false;
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}
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match stmt {
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Stmt::ReturnWithVal(_, _, _) | Stmt::Break(_) => {
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dead_code = true;
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}
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_ => (),
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}
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true
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});
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2020-03-18 03:36:50 +01:00
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// Change detection
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2020-03-13 11:12:41 +01:00
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if orig_len != result.len() {
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state.set_dirty();
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}
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2020-03-18 03:36:50 +01:00
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// Pop the stack and remove all the local constants
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2020-03-15 15:39:58 +01:00
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state.restore_constants(orig_constants_len);
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2020-03-09 14:57:07 +01:00
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match result[..] {
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2020-03-11 16:43:10 +01:00
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// No statements in block - change to No-op
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2020-03-09 14:57:07 +01:00
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[] => {
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2020-03-13 11:12:41 +01:00
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state.set_dirty();
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2020-03-10 04:22:41 +01:00
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Stmt::Noop(pos)
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}
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2020-03-11 16:43:10 +01:00
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// Only one statement - promote
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2020-03-09 14:57:07 +01:00
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[_] => {
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2020-03-13 11:12:41 +01:00
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state.set_dirty();
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2020-03-09 14:57:07 +01:00
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result.remove(0)
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}
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_ => Stmt::Block(result, pos),
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}
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}
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2020-03-18 03:36:50 +01:00
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// expr;
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2020-03-13 11:12:41 +01:00
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Stmt::Expr(expr) => Stmt::Expr(Box::new(optimize_expr(*expr, state))),
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2020-03-18 03:36:50 +01:00
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// return expr;
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2020-03-13 11:12:41 +01:00
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Stmt::ReturnWithVal(Some(expr), is_return, pos) => {
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|
|
Stmt::ReturnWithVal(Some(Box::new(optimize_expr(*expr, state))), is_return, pos)
|
|
|
|
}
|
2020-03-18 03:36:50 +01:00
|
|
|
// All other statements - skip
|
2020-03-11 16:43:10 +01:00
|
|
|
stmt => stmt,
|
2020-03-09 14:57:07 +01:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2020-03-18 03:36:50 +01:00
|
|
|
/// Optimize an expression.
|
2020-03-15 15:39:58 +01:00
|
|
|
fn optimize_expr<'a>(expr: Expr, state: &mut State<'a>) -> Expr {
|
2020-03-18 03:36:50 +01:00
|
|
|
// These keywords are handled specially
|
2020-03-19 12:53:42 +01:00
|
|
|
const DONT_EVAL_KEYWORDS: [&str; 3] = [KEYWORD_PRINT, KEYWORD_DEBUG, KEYWORD_EVAL];
|
2020-03-17 03:27:43 +01:00
|
|
|
|
2020-03-09 14:57:07 +01:00
|
|
|
match expr {
|
2020-03-18 03:36:50 +01:00
|
|
|
// ( stmt )
|
2020-03-13 11:12:41 +01:00
|
|
|
Expr::Stmt(stmt, pos) => match optimize_stmt(*stmt, state, true) {
|
2020-03-18 03:36:50 +01:00
|
|
|
// ( Noop ) -> ()
|
2020-03-09 14:57:07 +01:00
|
|
|
Stmt::Noop(_) => {
|
2020-03-13 11:12:41 +01:00
|
|
|
state.set_dirty();
|
2020-03-09 14:57:07 +01:00
|
|
|
Expr::Unit(pos)
|
|
|
|
}
|
2020-03-18 03:36:50 +01:00
|
|
|
// ( expr ) -> expr
|
2020-03-09 14:57:07 +01:00
|
|
|
Stmt::Expr(expr) => {
|
2020-03-13 11:12:41 +01:00
|
|
|
state.set_dirty();
|
2020-03-09 14:57:07 +01:00
|
|
|
*expr
|
|
|
|
}
|
2020-03-18 03:36:50 +01:00
|
|
|
// ( stmt )
|
2020-03-09 14:57:07 +01:00
|
|
|
stmt => Expr::Stmt(Box::new(stmt), pos),
|
|
|
|
},
|
2020-03-18 03:36:50 +01:00
|
|
|
// id = expr
|
|
|
|
Expr::Assignment(id, expr, pos) => match *expr {
|
|
|
|
//id = id2 = expr2
|
|
|
|
Expr::Assignment(id2, expr2, pos2) => match (*id, *id2) {
|
|
|
|
// var = var = expr2 -> var = expr2
|
|
|
|
(Expr::Variable(var, _), Expr::Variable(var2, _)) if var == var2 => {
|
2020-03-14 04:51:45 +01:00
|
|
|
// Assignment to the same variable - fold
|
|
|
|
state.set_dirty();
|
|
|
|
|
|
|
|
Expr::Assignment(
|
2020-03-18 03:36:50 +01:00
|
|
|
Box::new(Expr::Variable(var, pos)),
|
2020-03-14 04:51:45 +01:00
|
|
|
Box::new(optimize_expr(*expr2, state)),
|
2020-03-18 03:36:50 +01:00
|
|
|
pos,
|
2020-03-14 04:51:45 +01:00
|
|
|
)
|
|
|
|
}
|
2020-03-18 03:36:50 +01:00
|
|
|
// id1 = id2 = expr2
|
2020-03-14 04:51:45 +01:00
|
|
|
(id1, id2) => Expr::Assignment(
|
|
|
|
Box::new(id1),
|
|
|
|
Box::new(Expr::Assignment(
|
|
|
|
Box::new(id2),
|
|
|
|
Box::new(optimize_expr(*expr2, state)),
|
|
|
|
pos2,
|
|
|
|
)),
|
2020-03-18 03:36:50 +01:00
|
|
|
pos,
|
2020-03-14 04:51:45 +01:00
|
|
|
),
|
|
|
|
},
|
2020-03-18 03:36:50 +01:00
|
|
|
// id = expr
|
|
|
|
expr => Expr::Assignment(id, Box::new(optimize_expr(expr, state)), pos),
|
2020-03-14 04:51:45 +01:00
|
|
|
},
|
2020-03-18 03:36:50 +01:00
|
|
|
// lhs.rhs
|
2020-03-09 14:57:07 +01:00
|
|
|
Expr::Dot(lhs, rhs, pos) => Expr::Dot(
|
2020-03-13 11:12:41 +01:00
|
|
|
Box::new(optimize_expr(*lhs, state)),
|
|
|
|
Box::new(optimize_expr(*rhs, state)),
|
2020-03-09 14:57:07 +01:00
|
|
|
pos,
|
|
|
|
),
|
2020-03-11 04:03:18 +01:00
|
|
|
|
2020-03-18 03:36:50 +01:00
|
|
|
// lhs[rhs]
|
2020-03-10 10:10:33 +01:00
|
|
|
#[cfg(not(feature = "no_index"))]
|
|
|
|
Expr::Index(lhs, rhs, pos) => match (*lhs, *rhs) {
|
2020-03-18 03:36:50 +01:00
|
|
|
// array[int]
|
2020-03-10 10:10:33 +01:00
|
|
|
(Expr::Array(mut items, _), Expr::IntegerConstant(i, _))
|
2020-03-11 16:43:10 +01:00
|
|
|
if i >= 0 && (i as usize) < items.len() && items.iter().all(|x| x.is_pure()) =>
|
2020-03-10 10:10:33 +01:00
|
|
|
{
|
2020-03-16 05:41:52 +01:00
|
|
|
// Array literal where everything is pure - promote the indexed item.
|
2020-03-11 16:43:10 +01:00
|
|
|
// All other items can be thrown away.
|
2020-03-13 11:12:41 +01:00
|
|
|
state.set_dirty();
|
2020-03-10 10:10:33 +01:00
|
|
|
items.remove(i as usize)
|
|
|
|
}
|
2020-03-18 03:36:50 +01:00
|
|
|
// string[int]
|
2020-03-17 03:27:43 +01:00
|
|
|
(Expr::StringConstant(s, pos), Expr::IntegerConstant(i, _))
|
2020-03-16 05:41:52 +01:00
|
|
|
if i >= 0 && (i as usize) < s.chars().count() =>
|
|
|
|
{
|
|
|
|
// String literal indexing - get the character
|
|
|
|
state.set_dirty();
|
|
|
|
Expr::CharConstant(s.chars().nth(i as usize).expect("should get char"), pos)
|
|
|
|
}
|
2020-03-18 03:36:50 +01:00
|
|
|
// lhs[rhs]
|
2020-03-10 10:10:33 +01:00
|
|
|
(lhs, rhs) => Expr::Index(
|
2020-03-13 11:12:41 +01:00
|
|
|
Box::new(optimize_expr(lhs, state)),
|
|
|
|
Box::new(optimize_expr(rhs, state)),
|
2020-03-10 10:10:33 +01:00
|
|
|
pos,
|
|
|
|
),
|
|
|
|
},
|
2020-03-18 03:36:50 +01:00
|
|
|
// [ items .. ]
|
2020-03-10 10:10:33 +01:00
|
|
|
#[cfg(not(feature = "no_index"))]
|
2020-03-09 14:57:07 +01:00
|
|
|
Expr::Array(items, pos) => {
|
2020-03-12 07:54:14 +01:00
|
|
|
let orig_len = items.len();
|
2020-03-09 14:57:07 +01:00
|
|
|
|
|
|
|
let items: Vec<_> = items
|
|
|
|
.into_iter()
|
2020-03-13 11:12:41 +01:00
|
|
|
.map(|expr| optimize_expr(expr, state))
|
2020-03-09 14:57:07 +01:00
|
|
|
.collect();
|
|
|
|
|
2020-03-13 11:12:41 +01:00
|
|
|
if orig_len != items.len() {
|
|
|
|
state.set_dirty();
|
|
|
|
}
|
2020-03-09 14:57:07 +01:00
|
|
|
|
|
|
|
Expr::Array(items, pos)
|
|
|
|
}
|
2020-03-18 03:36:50 +01:00
|
|
|
// lhs && rhs
|
2020-03-09 14:57:07 +01:00
|
|
|
Expr::And(lhs, rhs) => match (*lhs, *rhs) {
|
2020-03-18 03:36:50 +01:00
|
|
|
// true && rhs -> rhs
|
2020-03-09 14:57:07 +01:00
|
|
|
(Expr::True(_), rhs) => {
|
2020-03-13 11:12:41 +01:00
|
|
|
state.set_dirty();
|
2020-03-09 14:57:07 +01:00
|
|
|
rhs
|
|
|
|
}
|
2020-03-18 03:36:50 +01:00
|
|
|
// false && rhs -> false
|
2020-03-09 14:57:07 +01:00
|
|
|
(Expr::False(pos), _) => {
|
2020-03-13 11:12:41 +01:00
|
|
|
state.set_dirty();
|
2020-03-09 14:57:07 +01:00
|
|
|
Expr::False(pos)
|
|
|
|
}
|
2020-03-18 03:36:50 +01:00
|
|
|
// lhs && true -> lhs
|
2020-03-09 14:57:07 +01:00
|
|
|
(lhs, Expr::True(_)) => {
|
2020-03-13 11:12:41 +01:00
|
|
|
state.set_dirty();
|
2020-03-18 03:36:50 +01:00
|
|
|
optimize_expr(lhs, state)
|
2020-03-09 14:57:07 +01:00
|
|
|
}
|
2020-03-18 03:36:50 +01:00
|
|
|
// lhs && rhs
|
2020-03-09 14:57:07 +01:00
|
|
|
(lhs, rhs) => Expr::And(
|
2020-03-13 11:12:41 +01:00
|
|
|
Box::new(optimize_expr(lhs, state)),
|
|
|
|
Box::new(optimize_expr(rhs, state)),
|
2020-03-09 14:57:07 +01:00
|
|
|
),
|
|
|
|
},
|
2020-03-18 03:36:50 +01:00
|
|
|
// lhs || rhs
|
2020-03-09 14:57:07 +01:00
|
|
|
Expr::Or(lhs, rhs) => match (*lhs, *rhs) {
|
2020-03-18 03:36:50 +01:00
|
|
|
// false || rhs -> rhs
|
2020-03-09 14:57:07 +01:00
|
|
|
(Expr::False(_), rhs) => {
|
2020-03-13 11:12:41 +01:00
|
|
|
state.set_dirty();
|
2020-03-09 14:57:07 +01:00
|
|
|
rhs
|
|
|
|
}
|
2020-03-18 03:36:50 +01:00
|
|
|
// true || rhs -> true
|
2020-03-09 14:57:07 +01:00
|
|
|
(Expr::True(pos), _) => {
|
2020-03-13 11:12:41 +01:00
|
|
|
state.set_dirty();
|
2020-03-09 14:57:07 +01:00
|
|
|
Expr::True(pos)
|
|
|
|
}
|
2020-03-18 03:36:50 +01:00
|
|
|
// lhs || false
|
2020-03-09 14:57:07 +01:00
|
|
|
(lhs, Expr::False(_)) => {
|
2020-03-13 11:12:41 +01:00
|
|
|
state.set_dirty();
|
2020-03-18 03:36:50 +01:00
|
|
|
optimize_expr(lhs, state)
|
2020-03-09 14:57:07 +01:00
|
|
|
}
|
2020-03-18 03:36:50 +01:00
|
|
|
// lhs || rhs
|
2020-03-09 14:57:07 +01:00
|
|
|
(lhs, rhs) => Expr::Or(
|
2020-03-13 11:12:41 +01:00
|
|
|
Box::new(optimize_expr(lhs, state)),
|
|
|
|
Box::new(optimize_expr(rhs, state)),
|
2020-03-09 14:57:07 +01:00
|
|
|
),
|
|
|
|
},
|
2020-03-11 16:43:10 +01:00
|
|
|
|
2020-03-19 12:53:42 +01:00
|
|
|
// Do not optimize anything within dump_ast
|
|
|
|
Expr::FunctionCall(id, args, def_value, pos) if id == KEYWORD_DUMP_AST =>
|
2020-03-17 03:27:43 +01:00
|
|
|
Expr::FunctionCall(id, args, def_value, pos),
|
|
|
|
|
2020-03-19 12:53:42 +01:00
|
|
|
// Do not optimize anything within built-in function keywords
|
|
|
|
Expr::FunctionCall(id, args, def_value, pos) if DONT_EVAL_KEYWORDS.contains(&id.as_str())=>
|
|
|
|
Expr::FunctionCall(id,
|
|
|
|
args.into_iter().map(|a| optimize_expr(a, state)).collect(),
|
|
|
|
def_value, pos),
|
|
|
|
|
2020-03-18 03:36:50 +01:00
|
|
|
// Eagerly call functions
|
2020-03-15 15:39:58 +01:00
|
|
|
Expr::FunctionCall(id, args, def_value, pos)
|
2020-03-18 03:36:50 +01:00
|
|
|
if state.engine.optimization_level == OptimizationLevel::Full // full optimizations
|
2020-03-15 15:39:58 +01:00
|
|
|
&& args.iter().all(|expr| expr.is_constant()) // all arguments are constants
|
2020-03-17 03:27:43 +01:00
|
|
|
=> {
|
2020-03-15 15:39:58 +01:00
|
|
|
let mut arg_values: Vec<_> = args.iter().map(Expr::get_constant_value).collect();
|
|
|
|
let call_args: FnCallArgs = arg_values.iter_mut().map(Dynamic::as_mut).collect();
|
2020-03-17 03:27:43 +01:00
|
|
|
|
|
|
|
// Save the typename of the first argument if it is `type_of()`
|
|
|
|
// This is to avoid `call_args` being passed into the closure
|
|
|
|
let arg_for_type_of = if id == KEYWORD_TYPE_OF && call_args.len() == 1 {
|
2020-03-18 03:36:50 +01:00
|
|
|
state.engine.map_type_name(call_args[0].type_name())
|
2020-03-17 03:27:43 +01:00
|
|
|
} else {
|
|
|
|
""
|
|
|
|
};
|
|
|
|
|
2020-03-18 03:36:50 +01:00
|
|
|
state.engine.call_ext_fn_raw(&id, call_args, pos).ok().map(|r|
|
2020-03-17 03:27:43 +01:00
|
|
|
r.or_else(|| {
|
|
|
|
if !arg_for_type_of.is_empty() {
|
|
|
|
// Handle `type_of()`
|
|
|
|
Some(arg_for_type_of.to_string().into_dynamic())
|
|
|
|
} else {
|
|
|
|
// Otherwise use the default value, if any
|
|
|
|
def_value.clone()
|
|
|
|
}
|
|
|
|
}).and_then(|result| map_dynamic_to_expr(result, pos).0)
|
2020-03-15 15:39:58 +01:00
|
|
|
.map(|expr| {
|
|
|
|
state.set_dirty();
|
|
|
|
expr
|
2020-03-17 03:27:43 +01:00
|
|
|
})
|
|
|
|
).flatten().unwrap_or_else(|| Expr::FunctionCall(id, args, def_value, pos))
|
2020-03-15 15:39:58 +01:00
|
|
|
}
|
2020-03-19 12:53:42 +01:00
|
|
|
|
2020-03-18 03:36:50 +01:00
|
|
|
// id(args ..) -> optimize function call arguments
|
2020-03-17 03:27:43 +01:00
|
|
|
Expr::FunctionCall(id, args, def_value, pos) =>
|
2020-03-19 12:53:42 +01:00
|
|
|
Expr::FunctionCall(id,
|
|
|
|
args.into_iter().map(|a| optimize_expr(a, state)).collect(),
|
|
|
|
def_value, pos),
|
|
|
|
|
2020-03-18 03:36:50 +01:00
|
|
|
// constant-name
|
2020-03-13 11:12:41 +01:00
|
|
|
Expr::Variable(ref name, _) if state.contains_constant(name) => {
|
|
|
|
state.set_dirty();
|
|
|
|
|
|
|
|
// Replace constant with value
|
|
|
|
state
|
|
|
|
.find_constant(name)
|
2020-03-15 15:39:58 +01:00
|
|
|
.expect("should find constant in scope!")
|
2020-03-13 11:12:41 +01:00
|
|
|
.clone()
|
|
|
|
}
|
2020-03-19 12:53:42 +01:00
|
|
|
|
2020-03-18 03:36:50 +01:00
|
|
|
// All other expressions - skip
|
2020-03-11 16:43:10 +01:00
|
|
|
expr => expr,
|
2020-03-09 14:57:07 +01:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2020-03-18 03:36:50 +01:00
|
|
|
pub(crate) fn optimize<'a>(statements: Vec<Stmt>, engine: &Engine<'a>, scope: &Scope) -> Vec<Stmt> {
|
2020-03-15 15:39:58 +01:00
|
|
|
// If optimization level is None then skip optimizing
|
2020-03-18 03:36:50 +01:00
|
|
|
if engine.optimization_level == OptimizationLevel::None {
|
2020-03-15 15:39:58 +01:00
|
|
|
return statements;
|
|
|
|
}
|
|
|
|
|
|
|
|
// Set up the state
|
2020-03-18 03:36:50 +01:00
|
|
|
let mut state = State {
|
|
|
|
changed: false,
|
|
|
|
constants: vec![],
|
|
|
|
engine,
|
|
|
|
};
|
2020-03-15 15:39:58 +01:00
|
|
|
|
2020-03-18 03:36:50 +01:00
|
|
|
// Add constants from the scope into the state
|
2020-03-15 15:39:58 +01:00
|
|
|
scope
|
|
|
|
.iter()
|
|
|
|
.filter(|ScopeEntry { var_type, expr, .. }| {
|
|
|
|
// Get all the constants with definite constant expressions
|
|
|
|
*var_type == VariableType::Constant
|
|
|
|
&& expr.as_ref().map(Expr::is_constant).unwrap_or(false)
|
|
|
|
})
|
|
|
|
.for_each(|ScopeEntry { name, expr, .. }| {
|
|
|
|
state.push_constant(
|
|
|
|
name.as_ref(),
|
|
|
|
expr.as_ref().expect("should be Some(expr)").clone(),
|
|
|
|
)
|
|
|
|
});
|
|
|
|
|
|
|
|
let orig_constants_len = state.constants.len();
|
|
|
|
|
2020-03-11 16:43:10 +01:00
|
|
|
let mut result = statements;
|
|
|
|
|
2020-03-18 03:36:50 +01:00
|
|
|
// Optimization loop
|
2020-03-09 14:57:07 +01:00
|
|
|
loop {
|
2020-03-15 15:39:58 +01:00
|
|
|
state.reset();
|
|
|
|
state.restore_constants(orig_constants_len);
|
2020-03-09 14:57:07 +01:00
|
|
|
|
2020-03-15 15:39:58 +01:00
|
|
|
let num_statements = result.len();
|
2020-03-14 07:30:44 +01:00
|
|
|
|
2020-03-11 16:43:10 +01:00
|
|
|
result = result
|
2020-03-09 14:57:07 +01:00
|
|
|
.into_iter()
|
2020-03-11 16:43:10 +01:00
|
|
|
.enumerate()
|
|
|
|
.map(|(i, stmt)| {
|
2020-03-13 11:12:41 +01:00
|
|
|
if let Stmt::Const(name, value, _) = &stmt {
|
|
|
|
// Load constants
|
|
|
|
state.push_constant(name, value.as_ref().clone());
|
2020-03-17 07:29:22 +01:00
|
|
|
stmt // Keep it in the global scope
|
2020-03-13 11:12:41 +01:00
|
|
|
} else {
|
|
|
|
// Keep all variable declarations at this level
|
|
|
|
// and always keep the last return value
|
2020-03-18 03:36:50 +01:00
|
|
|
let keep = matches!(stmt, Stmt::Let(_, _, _)) || i == num_statements - 1;
|
2020-03-13 11:12:41 +01:00
|
|
|
|
|
|
|
optimize_stmt(stmt, &mut state, keep)
|
|
|
|
}
|
2020-03-11 16:43:10 +01:00
|
|
|
})
|
2020-03-09 14:57:07 +01:00
|
|
|
.collect();
|
|
|
|
|
2020-03-13 11:12:41 +01:00
|
|
|
if !state.is_dirty() {
|
2020-03-09 14:57:07 +01:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2020-03-12 16:46:52 +01:00
|
|
|
// Eliminate code that is pure but always keep the last statement
|
2020-03-11 16:43:10 +01:00
|
|
|
let last_stmt = result.pop();
|
|
|
|
|
2020-03-17 07:29:22 +01:00
|
|
|
// Remove all pure statements at global level
|
2020-03-18 11:41:18 +01:00
|
|
|
result.retain(|stmt| !stmt.is_pure());
|
2020-03-11 16:43:10 +01:00
|
|
|
|
2020-03-18 11:41:18 +01:00
|
|
|
// Add back the last statement unless it is a lone No-op
|
2020-03-11 16:43:10 +01:00
|
|
|
if let Some(stmt) = last_stmt {
|
2020-03-18 11:41:18 +01:00
|
|
|
if result.len() > 0 || !matches!(stmt, Stmt::Noop(_)) {
|
|
|
|
result.push(stmt);
|
|
|
|
}
|
2020-03-11 16:43:10 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
result
|
2020-03-09 14:57:07 +01:00
|
|
|
}
|
2020-03-15 15:39:58 +01:00
|
|
|
|
2020-03-18 03:36:50 +01:00
|
|
|
/// Optimize an AST.
|
2020-03-18 11:41:18 +01:00
|
|
|
pub fn optimize_into_ast(
|
2020-03-15 15:39:58 +01:00
|
|
|
engine: &Engine,
|
|
|
|
scope: &Scope,
|
|
|
|
statements: Vec<Stmt>,
|
|
|
|
functions: Vec<FnDef>,
|
|
|
|
) -> AST {
|
|
|
|
AST(
|
|
|
|
match engine.optimization_level {
|
|
|
|
OptimizationLevel::None => statements,
|
2020-03-18 03:36:50 +01:00
|
|
|
OptimizationLevel::Simple => optimize(statements, engine, &scope),
|
|
|
|
OptimizationLevel::Full => optimize(statements, engine, &scope),
|
2020-03-15 15:39:58 +01:00
|
|
|
},
|
|
|
|
functions
|
|
|
|
.into_iter()
|
|
|
|
.map(|mut fn_def| {
|
|
|
|
match engine.optimization_level {
|
|
|
|
OptimizationLevel::None => (),
|
|
|
|
OptimizationLevel::Simple | OptimizationLevel::Full => {
|
|
|
|
let pos = fn_def.body.position();
|
2020-03-18 03:36:50 +01:00
|
|
|
|
|
|
|
// Optimize the function body
|
|
|
|
let mut body = optimize(vec![fn_def.body], engine, &Scope::new());
|
|
|
|
|
|
|
|
// {} -> Noop
|
2020-03-17 10:33:37 +01:00
|
|
|
fn_def.body = match body.pop().unwrap_or_else(|| Stmt::Noop(pos)) {
|
2020-03-18 03:36:50 +01:00
|
|
|
// { return val; } -> val
|
2020-03-17 10:33:37 +01:00
|
|
|
Stmt::ReturnWithVal(Some(val), ReturnType::Return, _) => {
|
|
|
|
Stmt::Expr(val)
|
|
|
|
}
|
2020-03-18 03:36:50 +01:00
|
|
|
// { return; } -> ()
|
2020-03-17 10:33:37 +01:00
|
|
|
Stmt::ReturnWithVal(None, ReturnType::Return, pos) => {
|
|
|
|
Stmt::Expr(Box::new(Expr::Unit(pos)))
|
|
|
|
}
|
2020-03-18 03:36:50 +01:00
|
|
|
// All others
|
2020-03-17 10:33:37 +01:00
|
|
|
stmt => stmt,
|
|
|
|
};
|
2020-03-15 15:39:58 +01:00
|
|
|
}
|
|
|
|
}
|
|
|
|
Arc::new(fn_def)
|
|
|
|
})
|
|
|
|
.collect(),
|
|
|
|
)
|
|
|
|
}
|